Sorry for the delay, wasn't ignoring your suggestion (and thanks for the code).

I figured it would be a bit cleaner to implement the filtering on the back-end and just pushed the code so feel free to give it a whirl. One of the benefits of doing it on the back-end (besides the speed) is that you end up with urls that you can bookmark if you just want to see the results from your properties.

The 1 year filtering works. I expect whatever you were looking for just wasn't tested that far back. The site only came online in February and if you do a 1 year filter for http://www.yahoo.com you will see tests going back that far: